Centrifugal pump.



M. B. MAGNEILL. C-ENTRIFUGAL PUMP. APPLICATION FILED AUG. 2, 1912 1 ,1 D5;8Q8. Patented Aug. 4, 1914 2 SHEBTS-SKBET 1.

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APPLICATION FILED AUG. 2, 1912. v

Patented Aug. 4, 1914.

2 8HEI1TB-SHEET 2.

4265565: WO /ill B Edema/Z 1618/ @AWV @M UNITED STATES PATENT OFFICE.

MARTIN B. MAGNEILL, 0F IBELOIT, WISCONSIN, ASSIGNOR TO FAIRBANKS, MORSE &

COMPANY, OF CHICAGO, ILLINOIS, A. CORPORATION 'OF ILLINOIS.

CENTRIFUG-AL PUMP.

Specification of Letters Patent.

Patented Aug. 4:, 19114.

To all whom it may concern Be it known that I, MARTIN B. MACNEILL, a citizen of the United States, residing at Beloit, in the county of Rock and State of Wisconsin, have invented a certain new and useful Improvement in Centrifugal Pumps, of which the following is a specificati0n.-

My invention has reference to centrifugal or turbine pumps of the single or multi stage type arranged for either horizontal or vertical operation, and relates more partlcularly to improved means for automatically counterbalancing the end thrust, thereby elim nating the friction losses of a thrust bearing and increasing the efliciency. My construction also greatly reduces the pressure at the stuffing box of the delivery end of multi stage pumps, obviating the troubles and friction losses inherent in a high pressure shaft packing.

Referring to the drawings which form part of this specification, Figure 1 is an axlal section of a horizontal single stage pump embodying my invention. Fig. 2 is a transverse sectional detail taken on the hue 2-2, Fig. 1. Fig. 3 is an enlarged longitudinal sectional detail of the balancing piston and associated parts which form importantelements of my invention. Fig. 4 is an anial section of a multi stage pump embodying my invention.

Similar numerals refer to similar parts in the different views.

The pump casing 1 is provided with an inlet 2 and a circumferential discharge passage 3 of ordinary construction. Said casing is provided with stuffing boxes 4: through which passes the main shaft 5 provided with a rotary impeller 6. On the inlet or suction side, the casing has an annular flange 7 which makes a running joint with a corre:

sponding annular flange 8 formed upon the impeller. Between the impeller and the easing are formed pressure chambers. 10 and 11, the pressure chamber 10 being on the inlet side and receiving the water which leaks past the joint between the periphery of the impeller and the discharge passage. 'Ehe water in the chamber .is therefore approximately at the same pressure as the water in the discharge. Pressure chamber 11 on the rear side of the impeller is, for similar reasons, filled with water at a pressure substantially equal to the pressure in the discharge.

A plate 12 is rigidly secured to the inside of the casing behind the impeller and practically forms a part of said casing. It constitutes a partition between the pressure chamber 11 and the balancing chamber 13. Said plate is centrally apertured and has an annular SllOllltlGl' 14 which makes a running joint with the shoulder 16 on the hub of the impeller. A balancing piston 17 is rigidly secured to the impeller shaft and forms the movable rear wall of the said balancing chamber. At its circular periphery said piston makes a running joint with a part of the casing, preferably the annular shoulder 15 formed on partition 12. In the present construction the impeller and balancing piston are held together as a single unit between a shoulder 18 on the shaft and a nut 19 screwing on said shaft.

Between the casing and the back of the piston is a duct or chamber 21 which is in constant communication with the inlet through one or more ducts 24: preferably passing longitudinally of the shaft through the hubs of the piston and impeller. A duct 25 is formed between the hub of the balancing piston and the inner opening of partition 12 to convey water from the pressure chamber 11 to the balancing chamber 13. The parts are so constructed that the periphery of the piston will just about meet the annular shoulder 15 when the annular shoulder 14 meets the shoulder 16 on the impeller hub. A movement of the piston to the right, therefore, will enlarge the passage between the balancing chamber and the duct 21 and simultaneously throttle the flow from the pressure chamber 11 into the balancing chamber. Conversely, a movement of the piston to the left will increase the flow from the pressure chamber into. the balancing chamber and simultaneously throttle the flow from the balancing chamber to the passage 21. It'inay be said therefore, that the rotor, which comprises the impeller and the balancing piston, makes two running joints with the pump casing and that these joints are oppositely faced, as a result whereof lateral movement of the impeller controls the pressure in the balancing chamber.

In operation, if the partition 12 and balancing piston were omitted the end thrust of the impeller would be toward the inlet or suction side; that is, toward the left in Figs. 1 and 41. This end thrust, of course, being due to the fact that a portion of the casing is cut away at the front of the impeller to form an inlet. In my pump, however, the

w front of the balancing piston has an area ment to move toward the left the impeller hub leaves the shoulder 14 and thus allows the pressure water in the casing to rush through duct 25 into the balancing chamber 13 where said pressure water will act upon the front of the piston and move it and the impeller toward the right. The result will be to cause the hub 16 to enter the annular shoulder 14 and throttle the flow of pressure'water into the balancing chamber and simultaneously cause the rim ofthe piston to leave the annular shoulder 15 and permit the escape of the pressure water from chamber 13 into duct 21, and? thence throughducts 24 into the inlet. practice, however, the rotating element will automatically find a certain position lat erally where the leakage past the impeller;

required pressure on the balancing pisto'n for effecting perfect balance.

The form of pump shown in Fig. i difiters. from that'hereinabove described merely in thenumber ofstages and the fact that the element 12 of Figs. 1 to 3 is made an int'egral part of the casing. In Fig. 4-, the

- fpump instead of being single stage, is multi stage, the first discharge passage 30 discharging into the inlet of the second impeller, the second discharge 31 discharging into the inlet of the third impeller, and the third discharge-32 delivering the water into the final outlet 33. The additional impellers,-however, do not modify in anyv essential the principle of operation'of the machine, the fundamental tendency of the end thrust being toward the left and this being automatically overcome by the balancing piston 17 constructed in. the same manner and performing the same function as the balancing piston already described;

It will be noted that in my construction the rotor hub coiiperates with the plate 12 5 shoulder to shoulder, that is, corner to cor ner, 'the result being that the aetion'in throttling or passing the water is much quickenthan it would otherwise be and. the balance of the pump is much more sensitive. The same is true in connection with the cotiperation between the balancing piston and the shoulder 15 on plate 12.. There is another advantage in employing interfitting shoulders or running joints, for example, suppose the piston 17 is partially within the chamber 13, a slight movement ofthe piston to the right or left will vary the distance between the shoulders H and 16 (and thus vary the low inte the chamber mosses {i claim as new-and desire to secure by Letters Patent, is:

1. In a centrifugal pump, a casing,.an

impeller in said casing, a piston behind said impeller ri 'idly connected thereto, said casing having a artition extending from 1t toward the mac ine axis, there being a pressure chamber between the partition and the rear of the impeller and a balancing chamber between the partition and the piston, a waste duct leading from said balancing chamber, a pair of coiiperating annug ar shoulders, one on said partition and the other on the impeller hub adapted to permit an increased flow from the pressure chamber into the balancing chamber when the impeller moves toward the pump inlet and hway from the pump inlet, and a second pgair of cooperating annular shoulders one I y :on said piston and the other on said casing hub will be just sufiicient to maintain the forward, said shoulders meeting corner to corner to thereby obtain a highly sensitive control.

2. In a centrifugal pump, turbine, or similar machine the combination of aoasing havin an inlet and a discharge, a rotary impe ler cooperating with the casing to form a pressure chamber between the casing and the rear of the impeller, a balancing piston at the rear of the impeller moving laterally in unison therewith, a centrally apertured partition in said casing formingthe rear of said pressure chamber and the frontof a balancin chamber, the rear of the balancing member being formed by the balancing piston, an annularshoulder formed on said partition concentric with the axis of the machine, a shoulder on said impeller 'tihrottle the flow when the impeller moves fitting the said shoulder on the partition.

other on said casing,v pan" ofshoulders being adapted.

to the balancing to permit increased flow from thebalancing chamber when the piston moves laterallytoward the rear and vice versa and a duct leading from the rim of the piston between the casing and the rear of the piston thence forward through the hubs of the piston and impeller to the inlet of the machine.

8. In a centrifugal pump, the combine its .ton behind said rotor rotatin tion of a casing, a rotor in said casing, said rotor having a hub with an annular'shoulder or corner formed thereon, a balancing pisin 111115011 therewith and having an annu ar shoulder or corner formed thereon, a pressure chamber and a balancing chamber formed in said casing behind said rotor, the balancing chamber being behind said pressure chamber, and a partition in said casing separating the pressure chamber from the balancing chamber and extending from the casing toward the rotor hub between the rotor and the balancing piston, and said partition having two annular shoulders or corners, one cooperating with the aforesaid shoulder on the hub and the other cooperating with the adjacent shoulder on the balancing piston,

substantially as described.

4. In a centrifugal pump, a casing, an impeller in said casing, a piston behind said impeller rigidly connected thereto, said oasing having a artition extendin from it toward the mac time axis, there being a pressure chamber between the partition and the rear .of the impeller and a'balancing chamber between the a waste duct lea ng from said balancing chamber, a pair, of cooperating annular (partition and the piston,

shoulders, one on said partition and the other on the impeller hub adapted to permit an increased flow from the pressure chamber into the balancin chamber when the impeller moves towar the pump inlet and throttle the flow when the impeller moves away from the: pump inlet, and a second pair of cooperating annular shoulders one on said piston and the other on said casing adapted to permit an increased flow from said balancing chamber to the waste duct when said impeller moves rearward and throttle'the flow when said impeller moves forward, said shoulder meeting corner to corner and the shoulders of one pair being capable of interfitting with each other, whereb a lateral movement of the impeller s possible which will hold the flow at the interfitting shoulders substantially constant and at the same time permit a varying flow at the other pair of shoulders.

In witness whereof, I have hereunto subscr'ibed my name in the presence of two witnesses.

MARTIN MAONEILL.

Witnesses:

W; O. ACKLEY, Fara T. MERRILL.

Copies of this patent may be obtained fOfflVQ cents each, by addleaeing the "Commissioner of Patents,

Washington, D. 0." 

